Heterogeneous ZnO@CF structures and their excellent microwave absorbing properties with thin thickness and low filling

•A simple preparation method to design carbon fiber and metal oxide heterostructures•ZnO@CF heterostructure is beneficial to electromagnetic wave absorption•The effective bandwidth of ZnO@CF heterostructure achieved 4.94 GHz at low filling content (20wt%) and ultra-thin thickness (1.5mm)•The effective bandwidth covered the whole 2-18 GHz band with the increase of thickness from 0.5 to 10 mm